UWB Radar: Vision through a wall Ondrej Sisma^ Alain Gaugue\, Christophe Liebe^ Jean-Marc Ogier ^ Laboratoire Informatique, Image et Interaction (L3i), Universite de La Rochelle Pole Science et Technologic, 17042 La Rochelle Cedex 1 sismaol@fel.cvutxz, christophe.liebe@univ-lr.fr Abstract. There exist a lot of methods for vision through an opaque medium. At present UWB (Ultra-Wideband) technology is used more and more because it is suitable for localization and detection of a human body behind a wall. First of all this paper describes known methods for vision through walls, which can be divided into two general groups - imaging and non-imaging systems. Secondly it describes the state of the art UWB radar for this application and its specifics. Finally it depicts our UWB radar system (centrefrequency4,7GHz) and our practical procedures relevant to the detection of a human body presented behind a concrete wall. Keywords: UWB, radar, through-the-wall surveillance, imaging system, non- imaging system, bistatic radar. 1 Introduction Detection of persons and things behind an opaque medium is a very interesting theme for a wide range of industries and in following years this issue will constitute a strategic point of applicability in biomedical engineering, security service, agricultural industry, etc. For example, a through-the-wall surveillance (TWS) could be utilized in searching for people in rubble and in buildings on fire. The military could use this technology for bomb-disposal, neutralization of aggressors, hostage rescue, etc. Different technologies are applicable for through-the-wall surveillance: radio frequency (RF) technologies (from the UHF radar to the submillimeter wave imager), acoustic, X-ray scanner. These all appear to offer a partial solution. The desire to see through a wall creates a technical conflict between the possibility of successfrilly penetrating the wall, which implies lower frequencies, and the possibility of obtaining maximum resolution for the image, which implies higher frequencies. Perhaps one exception to this is the X-ray system which provides both good resolution and good penetration, but is limited to very short ranges and has safety risks. The text below elaborates on vision through walls system based on radio frequency. These can be classed in two categories: low frequency non-imaging systems that have good wall penetration capabilities but low spatial resolution, and high frequency imaging systems with limited wall penetration capabilities. Please use the following format when citing this chapter: Sisma, O., Gaugue, A., Liebe, C, Ogier, J.-M., 2007, in IFIP International Federation for Information Processing, Volume 245, Personal Wireless Communications, eds. Simak, B., Bestak, R., Kozowska, E., (Boston: Springer), pp. 241-251.